AIMS AND OBJECTIVES:
1. To study the Neuroimaging findings in patients presenting with various patterns of Siezure disorder using Magnetic Resonance Imaging.
2. To measure the Hippocampal volume in MRI in seizure disorder patients with no structural lesions or any visually detectable changes on routine assessment.
MATERIALS AND METHODS:
Source of Data:
This study was conducted at Mahatma Gandhi Memorial Government Hospital, Trichy in collaboration with Department of Radiology.
Study Design: Descriptive study.
Period of Study: January 2014 to September 2014.
Inclusion Criteria:
1. Age > 12.
2. Documented history of convulsion, who have MRI brain done on them as Out-patient or inpatient.
3. Consent to the study (patient and /or patient’s legal guardian).
Exclusion Criteria:
1. Age < 12.
2. Diabetic, chronic renal disease, suspected metabolic encephalopathy
3. Patients with convulsions with history of acute antecedent events like Trauma, Drugs, toxins, fever.
Method:
In this study ,56 participants aged >12 presenting with seizure as OUTPATIENT/INPATIENT in Medicine department between January 2014 and September 2014were studied after getting informed consent from patient and /or legal guardian. History taking and clinical examination was done and recorded in the form of a proforma. History included age, sex, duration of seizure, type of seizure, time, any predisposing factors, antecedent events if any, pork ingestion, contact with open case of tuberculosis etc. Detailed ,head to foot, examination including examination for any focal neurological deficit was done. Neuro imaging (MRI) was obtained after stabilization.
In those imaging studies where no obvious visually detectable changes were found, hippocampal volumetry was done using these steps:
• Acquisition of MRI slices (coronal) and evaluation in a DICOM viewer(radiant) and exporting them in the form of JPEG image.
• Creating stacks of image slices IMAGE J software.
• Marking REGION OF INTEREST on the stacked image and measuring the area of it.
• Area is the multiplied with the number of slices stacked varying per viewer/and or patient.
• Sum of these values per slice is used to calculate volume of 3D structure.
• The acquired data is entered into a MICROSOFT EXCEL sheet and analysed.
Statistical Analysis:
Statistical analysis was done by using percentages, mean values, standard deviation, standard error, chi square tests. SPSS version 20 was used to analyse data. The level of significance used was 0.05 levels for the corresponding degree of freedom to draw the inference. A p-value 0.05 was considered to be not statistically significant.
SUMMARY:
1. The most common type of seizure in adults is GTCS
2. The predominant type of seizure in
a) 12-20 age group is partial seizure(simple and complex with or without secondary generalization);
b) 21-40 age group shows a predominance in GTCS;
c) 41 to 65 age group shows an equal prevalence of GTCS and Partial seizures.
d) Absence seizure was reported only in 12-20 age group
3. Normal imaging in MRI is most commonly associated with GTCS type of seizure.
4. Focal and complex partial seizures are predominantly associated with neuroimaging abnormalities.
5. Most common MRI finding in SEIZURE patients is Normal study.
6. Every patient with epilepsy invariably needs an MRI for complete evaluation.
7. Tuberculomas are amongst the most common finding in IMAGE POSITIVE MRI results.
8. Hippocampal volumetry revealed gross volume regression in 2 subjects with one bilateral regression.
9. 8 cases out of the 19 with MRI NEGATIVE SEIZURES had significant variability in Interhippocampal volume difference from the mean IHD.
10. Correlation between IHD and duration of seizure is equivocal.
11. One subject showed a significant unilateral hippocampal regression on volumetry who may be a potential candidate for epilepsy surgery and needs further work up.
12. There is correlation between age and Total Hippocampal Volume with a peak Hippocampal volume in the 31-40 age range.
CONCLUSION :
1. History and physical examination have no substitute.
2. MRI is more sensitive and specific for imaging in patients with seizure than CT.
3. Hippocampal volumetry is essential in patients with MRI negative seizures in setups where investigations like fMRI, SPECT and PET are unavailable.
4. More extensive studies with longer term and larger population of study are required before we can establish a clear set of guidelines.
5. Further investigation and information regarding an option of Epilepsy surgery should be offered to the patients with unilateral Hippocampal regression on volumetry as they may progress to Refractory Epilepsy.
6. Subjects with significant variability in Inter Hippocampal volume difference need regular follow up with imaging to rule out the development of Hippocampal regression
